There is known a portable terminal device provided with a chassis in which at least one of a microphone and a receiver is installed. The microphone converts sound into electrical signals. The receiver converts electrical signals into sound. The chassis is provided with an opening communicated to the microphone or the receiver. The opening is positionally set such that an axis thereof passes through the microphone or the receiver. Japanese Unexamined Patent Application Publication No. 2004-56165 discloses the technology relating to such a portable terminal device.
However, it is conceivable that the opening is arranged apart from the opening, the microphone in light of design characteristics of the chassis. In this case, if water enters a passageway from the opening to the microphone or the receiver, the water might be retained in the passageway. The water retained in the passageway might influence acoustical characteristics.